Introduction to Cell Structure and Function, Mechanisms of Protein Transport in Eukaryotic Cells, Actin Polymerization and Muscle Contraction Mechanisms, Dynamic Instability and Structure of Cytoskeletal Filaments, Carbohydrate Metabolism Overview an…

Subcellular Fractionation

Separation of cellular components for analysis.

Peptidoglycan

Polymer forming prokaryotic cell walls.

NAD

Coenzyme involved in redox reactions.

Immune Receptors

Detect bacterial infections via peptidoglycan.

Kupffer Cell

Specialized liver macrophage removing blood particulates.

Supernatant

Liquid remaining after centrifugation of cell components.

Pellet

Solid residue collected after centrifugation.

Cell Lysing

Process of breaking open cells to study contents.

Intracellular Protein Transport

Mechanisms for moving proteins within cells.

Nuclear Pores

Entry and exit sites for nuclear transport.

Endoplasmic Reticulum (ER)

Organelle for protein synthesis and processing.

Transport Vesicles

Membrane-bound carriers for protein transport.

KEDL

Signal sequence for ER localization.

Nuclear Localisation Sequence (NLS)

Sequence required for nuclear protein entry.

Nucleoporins

Proteins forming nuclear pore complexes.

Nuclear Transport Receptors

Proteins guiding cargo into the nucleus.

GTP Hydrolysis

Energy source for nuclear transport processes.

Ran-GTP

Protein facilitating nuclear transport receptor function.

Translocase of the Inner Membrane (TIM)

Complex for mitochondrial protein import.

Transporter Outer Membrane (TOM)

Complex recognizing mitochondrial signal sequences.

Endomembrane System

Network of membranes for cellular transport.

Free Ribosomes

Ribosomes not attached to ER, synthesizing cytosolic proteins.

Protein Fibrils

Structures projecting from nuclear pore complexes.

Cytosolic Proteins

Proteins functioning within the cytosol.

Signal Peptidase

Enzyme that cleaves signal sequence post-translocation.

Polyribosome

Multiple ribosomes translating a single mRNA molecule.

Signal Recognition Particle (SRP)

Guides ribosomes to ER for protein translocation.

Translocation Channel

Channel in ER membrane for protein transport.

Water-Soluble Proteins

Proteins that completely cross ER membrane into lumen.

Transmembrane Proteins

Proteins that partially embed in the ER membrane.

Membrane-Spanning Segment

Region anchoring transmembrane proteins in lipid bilayer.

Cleavage

Process of removing the signal sequence from proteins.

Affinity

Attraction between signal sequence and mitochondrial receptor.

ER Signal Sequence

Hydrophobic amino acids directing proteins to the ER.

Lumen

Interior space of the ER where proteins are released.

Hydrophobic Amino Acids

Amino acids that facilitate membrane protein insertion.

Contact Site

Area where mitochondrial membranes are closely aligned.

Backsliding Prevention

Chaperone proteins prevent proteins from exiting translocation.

Multi-Pass Proteins

Proteins with multiple hydrophobic regions spanning membranes.

Translocation

Process of moving proteins across membranes.

Multi-pass Membrane Proteins

Proteins that span the lipid bilayer multiple times.

Budding

Process of vesicle formation from membranes.

Fusion

Joining of vesicles with target membranes.

Invagination

Folding of the plasma membrane to form vesicles.

Protein Coat

Layer of proteins shaping vesicles during budding.

Clathrin

Protein involved in forming vesicle coats.

Cargo Molecules

Substances transported within vesicles.

Adaptins

Proteins linking receptors to clathrin molecules.

Triskelions

Clathrin molecules forming a three-legged structure.

Cytoskeletal Fibres

Structures aiding in vesicle transport within cells.

Constitutive Secretion

Continuous release of proteins by cells.

Signal-Dependent Secretion

Release of proteins triggered by specific signals.

LDL (Low-Density Lipoprotein)

Transporter of cholesterol in the bloodstream.

Phagocytosis

Uptake of large particles or cells by vesicles.

Autophagy

Degradation of cellular components via lysosomes.

Endosomes

Compartment sorting internalized materials.

Lysosomes

Organelles for intracellular digestion.

Hydrolytic Enzymes

Enzymes that break down biomolecules in lysosomes.

Membrane-Mediated Uptake

Transport involving vesicles derived from membranes.

Receptor-Mediated Endocytosis

Specific uptake of molecules via receptor binding.

Vesicular Uptake

Process of internalizing substances via vesicles.

Insulin Secretion

Release of insulin via vesicle fusion with membrane.

Protein Translocators

Membrane proteins facilitating entry into organelles.

Actin Polymerisation

Multi-step process involving nucleation, elongation, steady state.

Nucleation

Rate-limiting stage requiring three actin monomers.

Critical Concentration (Cc)

Concentration where actin polymerisation is balanced.

Lamellipodia

Protrusions formed by actin at cell's leading edge.

Filopodia

Thin, spike-like extensions of crawling cells.

Myosins

Motor proteins that hydrolyze ATP to move along actin.

Myosin II

Muscle myosin composed of heavy and light chains.

Myofibrils

Contractile elements of muscle fibers, composed of sarcomeres.

Sarcomeres

Basic contractile units of muscle, aligned in myofibrils.

M-line

Protein structure linking thick myosin filaments.

Z-disc

Attachment site for thin actin filaments.

A bands

Dark bands in muscle, containing thick filaments.

I bands

Light bands in muscle, containing thin filaments.

Overlap Region

Area where actin and myosin filaments interact.

Muscle Contraction

Myosin and actin slide past each other.

Calcium Regulation

Troponin and tropomyosin mediate calcium's effect on contraction.

Actin Myopathy

Condition caused by ACTA1 gene mutations, leading to weakness.

Familial Hypertrophic Cardiomyopathy

Condition from mutations in cardiac myosin affecting heart function.

T Tubules

Extensions of muscle plasma membrane involved in contraction.

Sarcoplasmic Reticulum

Organelle releasing Ca2+ for muscle contraction.

ATPase Activity

Myosin heads hydrolyze ATP for movement along actin.

Filament Strength

Large number of weak bonds provide overall strength.

Crawling Cell Mechanism

Actin monomers add to plus ends, pushing membrane.

Motor Nerve Action

Triggers action potential leading to muscle contraction.

Calcium Pumping

Ca2+ returned to sarcoplasmic reticulum for relaxation.

Weak Non-Covalent Bonds

Individually weak, but collectively provide muscle strength.

Actin filaments

Also known as microfilaments; involved in cell motility.

Microtubules

Hollow cylinders made of tubulin; ~25nm diameter.

Intermediate filaments

Provide structural support; vary by cell type.

Dynamic instability

Microtubule growth and shrinkage phases alternate.

GTP-tubulin

Tubulin bound to GTP; promotes microtubule growth.

GDP-tubulin

Tubulin bound to GDP; associated with microtubule shrinkage.

Kinesins

Motor proteins that move towards the plus end of MTs.

Dyneins

Motor proteins that move towards the minus end of MTs.

Flagella

Whip-like structures enabling swimming in liquid media.

Axoneme

Core structure of cilia and flagella; '9 + 2' arrangement.

Basal bodies

Centrioles forming the base of cilia and flagella.